space_map.h revision 2e4c998613148111f2fc5371085331ffb39122ff
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
*/
#ifndef _SYS_SPACE_MAP_H
#define _SYS_SPACE_MAP_H
#include <sys/avl.h>
#include <sys/range_tree.h>
#include <sys/dmu.h>
#ifdef __cplusplus
extern "C" {
#endif
/*
* The size of the space map object has increased to include a histogram.
* The SPACE_MAP_SIZE_V0 designates the original size and is used to
* maintain backward compatibility.
*/
#define SPACE_MAP_SIZE_V0 (3 * sizeof (uint64_t))
#define SPACE_MAP_HISTOGRAM_SIZE 32
/*
* The space_map_phys is the on-disk representation of the space map.
* Consumers of space maps should never reference any of the members of this
* structure directly. These members may only be updated in syncing context.
*
* Note the smp_object is no longer used but remains in the structure
* for backward compatibility.
*/
typedef struct space_map_phys {
uint64_t smp_object; /* on-disk space map object */
uint64_t smp_objsize; /* size of the object */
uint64_t smp_alloc; /* space allocated from the map */
uint64_t smp_pad[5]; /* reserved */
/*
* The smp_histogram maintains a histogram of free regions. Each
* bucket, smp_histogram[i], contains the number of free regions
* whose size is:
* 2^(i+sm_shift) <= size of free region in bytes < 2^(i+sm_shift+1)
*/
uint64_t smp_histogram[SPACE_MAP_HISTOGRAM_SIZE];
} space_map_phys_t;
/*
* The space map object defines a region of space, its size, how much is
* allocated, and the on-disk object that stores this information.
* Consumers of space maps may only access the members of this structure.
*/
typedef struct space_map {
uint64_t sm_start; /* start of map */
uint64_t sm_size; /* size of map */
uint8_t sm_shift; /* unit shift */
uint64_t sm_length; /* synced length */
uint64_t sm_alloc; /* synced space allocated */
objset_t *sm_os; /* objset for this map */
uint64_t sm_object; /* object id for this map */
uint32_t sm_blksz; /* block size for space map */
dmu_buf_t *sm_dbuf; /* space_map_phys_t dbuf */
space_map_phys_t *sm_phys; /* on-disk space map */
kmutex_t *sm_lock; /* pointer to lock that protects map */
} space_map_t;
/*
* debug entry
*
* 1 3 10 50
* ,---+--------+------------+---------------------------------.
* | 1 | action | syncpass | txg (lower bits) |
* `---+--------+------------+---------------------------------'
* 63 62 60 59 50 49 0
*
*
* non-debug entry
*
* 1 47 1 15
* ,-----------------------------------------------------------.
* | 0 | offset (sm_shift units) | type | run |
* `-----------------------------------------------------------'
* 63 62 17 16 15 0
*/
/* All this stuff takes and returns bytes */
#define SM_RUN_DECODE(x) (BF64_DECODE(x, 0, 15) + 1)
#define SM_RUN_ENCODE(x) BF64_ENCODE((x) - 1, 0, 15)
#define SM_TYPE_DECODE(x) BF64_DECODE(x, 15, 1)
#define SM_TYPE_ENCODE(x) BF64_ENCODE(x, 15, 1)
#define SM_OFFSET_DECODE(x) BF64_DECODE(x, 16, 47)
#define SM_OFFSET_ENCODE(x) BF64_ENCODE(x, 16, 47)
#define SM_DEBUG_DECODE(x) BF64_DECODE(x, 63, 1)
#define SM_DEBUG_ENCODE(x) BF64_ENCODE(x, 63, 1)
#define SM_DEBUG_ACTION_DECODE(x) BF64_DECODE(x, 60, 3)
#define SM_DEBUG_ACTION_ENCODE(x) BF64_ENCODE(x, 60, 3)
#define SM_DEBUG_SYNCPASS_DECODE(x) BF64_DECODE(x, 50, 10)
#define SM_DEBUG_SYNCPASS_ENCODE(x) BF64_ENCODE(x, 50, 10)
#define SM_DEBUG_TXG_DECODE(x) BF64_DECODE(x, 0, 50)
#define SM_DEBUG_TXG_ENCODE(x) BF64_ENCODE(x, 0, 50)
#define SM_RUN_MAX SM_RUN_DECODE(~0ULL)
typedef enum {
SM_ALLOC,
SM_FREE
} maptype_t;
/*
* The data for a given space map can be kept on blocks of any size.
* Larger blocks entail fewer i/o operations, but they also cause the
* DMU to keep more data in-core, and also to waste more i/o bandwidth
* when only a few blocks have changed since the last transaction group.
* Rather than having a fixed block size for all space maps the block size
* can adjust as needed (see space_map_max_blksz). Set the initial block
* size for the space map to 4k.
*/
#define SPACE_MAP_INITIAL_BLOCKSIZE (1ULL << 12)
int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
void space_map_histogram_clear(space_map_t *sm);
void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
dmu_tx_t *tx);
void space_map_update(space_map_t *sm);
uint64_t space_map_object(space_map_t *sm);
uint64_t space_map_allocated(space_map_t *sm);
uint64_t space_map_length(space_map_t *sm);
void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
dmu_tx_t *tx);
void space_map_truncate(space_map_t *sm, dmu_tx_t *tx);
uint64_t space_map_alloc(objset_t *os, dmu_tx_t *tx);
void space_map_free(space_map_t *sm, dmu_tx_t *tx);
int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
uint64_t start, uint64_t size, uint8_t shift, kmutex_t *lp);
void space_map_close(space_map_t *sm);
int64_t space_map_alloc_delta(space_map_t *sm);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_SPACE_MAP_H */